20861667456 has 128 divisors (see below), whose sum is σ = 64403942400. Its totient is φ = 5859406848.

The previous prime is 20861667401. The next prime is 20861667461. The reversal of 20861667456 is 65476616802.

It is a tau number, because it is divible by the number of its divisors (128).

It is a junction number, because it is equal to n+sod(n) for n = 20861667399 and 20861667408.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 92821 + ... + 224363.

It is an arithmetic number, because the mean of its divisors is an integer number (503155800).

Almost surely, 2^20861667456 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20861667456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32201971200).

20861667456 is an abundant number, since it is smaller than the sum of its proper divisors (43542274944).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20861667456 is a wasteful number, since it uses less digits than its factorization.

20861667456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131626 (or 131614 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 51.

The spelling of 20861667456 in words is "twenty billion, eight hundred sixty-one million, six hundred sixty-seven thousand, four hundred fifty-six".